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How to make the myIDE II work on a Atari 800 with Incognito


tf_hh

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Hi,

 

yesterday I´ve found an interesting thing, which I didn´t know until now. On pin "S" of the cartridge-slots of an Atari 800 there´s not the "PHI2" signal attached as on all newer machines - there´s "RAS" connected. The falling edge of PHI2 and RAS is nearly the same, but RAS is much shorter low than PHI2 (of course, there must be some time for CAS, too).

 

Most modern circuits (in flash-carts or flashable carts) sample the PHI2 signal for their logic. So I think, this might be most significant reason for problems while writing to flash-memory or using special carts like the myIDE II.

 

See the signals on the scope:

 

post-15670-0-25978700-1368178255_thumb.jpg

 

So I try a little modification and use PHI2 on pin "S" instead of RAS. And these seems to be the solution... myIDE-II works now without any issues in an Atari 800 with Incognito. Also some other carts with suspicious failures works now.

 

I test this on two Atari 800 equipped with Incognito. On one machine I take the Incognito out and re-install the old genuine personaliy and RAM cards. Also everything works fine. I have only one cartridge with "Write to cart" features which works on the original old 800 system: Telelink II. But this also works fine with that patch.

 

If you want to do this patch by yourself, here´s a possible way:

 

post-15670-0-90018200-1368178262_thumb.jpg

 

Cut the RAS trace on the place in the picture.

 

post-15670-0-48702600-1368178269_thumb.jpg

 

Connect pin "A" and pin "S" on the "right" cartridge slot together - that´s all!

 

This mod is independent which TV system you have, it works also on NTSC as on PAL or SECAM.

 

Regards, Jurgen

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  • 4 weeks later...

What you´re waiting for? It´s a simple, reversible mod and of course I test it with a bunch of carts :)

 

Candle has mentioned it in the "beta" version (of maybe already final) of the "Incognito 400" schematics.

I don't have my myIDE II anymore, and I wanted to see how well this worked before buying another. Any incompatibilities so far? Does this work on all Atari 800's?

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Nobody can give you an 100% answer to the question "Does it work on ALL Atari 800´s"... :!:

 

I test it with a NTSC Atari 800 and a PAL one. I never see different versions of the main PCB. The connection of RAS instead of PHI2 to the desired pin if the cart ports are described in the official Atari Hardware Manual for 400 and 800 computers and also be shown in the schematics.

 

I personally never heard of any other flash-based cartridge working with a genuine 800 or 400. The most modern solutions require an XL/XE, most of them also requires SDX (for flashing only, not for usage). Both you can´t have on a stock 800 - until Incognito comes.

 

Jurgen

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I personally never heard of any other flash-based cartridge working with a genuine 800 or 400. The most modern solutions require an XL/XE, most of them also requires SDX (for flashing only, not for usage). Both you can´t have on a stock 800 - until Incognito comes.

Actually the old AtariMax flash cart did. I used it on my Atari 800 before packing it up.

 

So the reason the myIDE II works on the 800 now is because of Incognito? Interesting. I'll have to buy another one now I suppose. :)

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Somewhere (I think it was AtariMax support forums) I read that myIDE-II doesn´t with with genuine Atari 800 ("Colleen"). But with XL/XE it works fine. And with Incognito (and my suggested patch) an Atari 800 _is_ like XL/XE :)

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I just tried this modification. I should probably have tested things before I started.

 

MyIDE-II mostly works. MyDOS is fine, but whenever I try and use the Fat32 loader I get a message I need at least 512Kb ram.. which I have configured in Incognito.

 

When I use MyIDE-1 the Fat 32 Loader (called SIDE) works fine but MyDOS doesn't start up correctly.

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I just tried this modification. I should probably have tested things before I started.

 

MyIDE-II mostly works. MyDOS is fine, but whenever I try and use the Fat32 loader I get a message I need at least 512Kb ram.. which I have configured in Incognito.

 

When I use MyIDE-1 the Fat 32 Loader (called SIDE) works fine but MyDOS doesn't start up correctly.

 

Hi!

 

The reason that the FAT32 loader asks for 512KB does not mean that your atari needs 512KB (!!) it is the 512KB Sram from the MyIDE II interface that it is looking for. Abviously the atari 800 hack does not apply to the specs the MyIDE II needs to work properly.

 

So do not think in the direction of more or compatible memory inside your atari 800. It is the 512KB SRAM that is in the MyIDE II interface that can not be accessed properly obviously.

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  • 11 months later...

Hmm I have done this mod today, which is excellent btw (I needed it for THE!CART and The Mega Cart, which cured 100% of the issues with these carts).

 

But… the MyIDE is a different story indeed.

 

The Flash part of the MyIDE cartridge works, but the SRAM (which goes through the CLPD) isn't accessible.

 

Is there any difference in Atari 800 hardware when it comes to $d500-$d57f?

 

I'll try to write a routine that switches the green MyIDE ][ Led on and off.

 

If that works, I'll investigate SRAM.

 

I think the FAT32 loader writes some kind of random bytes to the SRAM of MyIDE ][ and then read those bytes back. If they don't match, it probably responds with that 512kB message.

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Well.. I have tested the MyIDE ][ cart in my Atari 800 and both the green CF-card led and the SRAM do work perfect; so IMHO there is no reason why FAT32 loader gives an error.

 

I don't know whether Steven Tucker booby-trapped his FAT32 loader with checksums, otherwise someone could de-activate that check.

 

Perhaps I'll take a look at that.

 

I have tested this on a non-incognito atari 800. I put an assembler on the FLASH part of the MyIDE ][ interface. I wrote a routine that copies the entire (running) assembler into SRAM. And I wrote a routine that switches the CF led on (and off).

 

Nothing interesting for you to run, so no XEX here, but only a test result.

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What you´re waiting for? It´s a simple, reversible mod and of course I test it with a bunch of carts :)

 

Candle has mentioned it in the "beta" version (of maybe already final) of the "Incognito 400" schematics.

 

Can I perform this modification in my Atari 400? Since it does not have two cart ports, how should I do it?

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When I look in the schematic of the 400 I have from Jerzy Sobola I see that the Ph2 that comes from PIA goes to PIN S of the cart port. You'd say, that's ok... but it is also connected to RAS of RAM. So the RAS pin of RAM is on the 400 connected with Ph2 and RAS. Isn't that strange and unwanted?

 

I have some stability issues when I use modern carts on my 400. It's not the issue you get with the 800, but other strange behavior (especially with AtariMax 1Mbit and AtariMax 8Mbit carts) ...

 

Is there a slight chance that when I do some changes (Ram pin 14 is connected with RAS only, and Cart Port S is connected with Ph2 only) that this might change something or is it not important what I found? Thanks

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Ok... did some checkings myself now.

 

The PH2 connection to S isn't there on the 400 at all. (Again a mistake in the schematic). In the 400 S is also RAS. So I fixed that.

 

My problems with AtariMax 1Mbit carts are gone now. With the AtariMax 8Mbit I still have issues. I have to check for that, but first I'll wait for my 48K upgrade from Best. I did my own piggyback sh*t now on a 16K board, which works fabulous, but since RD4 and RD5 are involved on this upgrade too, I can't be sure that my issues with the AtariMax 8Mbit cart are also caused by slight timing issues. (I don't have a scope or something like that).

 

I think the original 48K upgrade is more reliable than home-made-piggy-back spaghetti ... so before I go fixing more on my 400, I'll better wait.

 

Glad that I did the Ph2 fix now on my 400. Getting better and better everytime.

 

Greetz

Marius

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  • 3 years later...
  • 3 weeks later...

I currenty done my mod on a Atari 800 and here is a picture how to to the mod only on solder side of the Atari 800 Main PCB

atari-800-solder-side-fix.jpg

Thank you (and others) for your continued research! Especially tf_hh - this is an amazing discovery. Atari 800 owners must not be left behind - it was my first computer as a 10-year old kid. Now we can have access to so much more storage/accessibility options. This forum is a boon to an old kid.

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This was originally discovered during when new carts stopped working, blob on a pcb, and then the PBI mod, then rediscovered, rediscovered yet again during incognito, then for MyIDE and and probably will be discovered another time... :) so much discovering over the years!

Edited by _The Doctor__
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Ok... did some checkings myself now.

 

The PH2 connection to S isn't there on the 400 at all. (Again a mistake in the schematic). In the 400 S is also RAS. So I fixed that.

 

My problems with AtariMax 1Mbit carts are gone now. With the AtariMax 8Mbit I still have issues. I have to check for that, but first I'll wait for my 48K upgrade from Best. I did my own piggyback sh*t now on a 16K board, which works fabulous, but since RD4 and RD5 are involved on this upgrade too, I can't be sure that my issues with the AtariMax 8Mbit cart are also caused by slight timing issues. (I don't have a scope or something like that).

 

I think the original 48K upgrade is more reliable than home-made-piggy-back spaghetti ... so before I go fixing more on my 400, I'll better wait.

 

Glad that I did the Ph2 fix now on my 400. Getting better and better everytime.

 

Any chance someone could post a pic of a successful 400 mod for those of us who can barely swing a soldering iron but fail at relating schematics to real world circuit boards? When I see a picture like the 800 above with "cut here" and "add a wire here" I am confident I can perform this without butchering my board.

 

As the very early thread mentions that the arrival of Incognito would obviate this mod, does it still make sense to perform it on an 800 when installing Incognito or is it superfluous in that case?

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Hi,

 

 

Any chance someone could post a pic of a successful 400 mod for those of us who can barely swing a soldering iron but fail at relating schematics to real world circuit boards?

 

The Atari 400 has PHI2 to the named pin connected, so there´s no need for a patch.

 

BR Jurgen

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